Color correction apparatus for panorama video stitching and method for selecting reference image using the same

Abstract

Disclosed are a color correction apparatus for panorama video stitching and a method of selecting a reference image using the same. A method of selecting a reference image for color correction when stitching panorama video based on input images includes selecting an optimum reference image candidate from the input images based on standard deviations for overlapping regions between the input images, performing color correction on the input images based on the optimum reference image candidate, and validating the optimum reference image candidate based on the color-corrected input images.

What is claimed is: 
     
         1 . A method of selecting a reference image for color correction when stitching panorama video based on input images, the method comprising:
 selecting an optimum reference image candidate from the input images based on standard deviations for overlapping regions between the input images;   performing color correction on the input images based on the optimum reference image candidate; and   validating the optimum reference image candidate based on the color-corrected input images.   
     
     
         2 . The method of  claim 1 , wherein the validating of the optimum reference image candidate comprises:
 deriving a comparison value between the color-corrected input images and the input images prior to the color correction; and   determining the optimum reference image candidate to be a final reference image depending on whether or not the comparison value satisfies a predetermined threshold,   wherein the comparison value comprises at least one of a contrast value, an edge preservation value, and a value indicative of a percentage change in a saturation of color between the color-corrected input images and the input images prior to the color correction.   
     
     
         3 . The method of  claim 2 , further comprising selecting a next optimum reference image candidate from the input images based on the standard deviation if, as a result of the determination, it is determined that the comparison value does not satisfy the predetermined threshold. 
     
     
         4 . The method of  claim 2 , further comprising changing the predetermined threshold if the final reference image is not present in the input images and deriving the final reference image based on the changed threshold. 
     
     
         5 . The method of  claim 1 , wherein the selecting of the optimum reference image candidate comprises:
 calculating a standard deviation for an overlapping region between two neighboring input images after geometric correction is performed on the input images;   calculating a standard deviation difference value for each of the input images based on the standard deviation; and   ranking a suitability of the input images for selecting the optimum reference image candidate based on the standard deviation difference value.   
     
     
         6 . The method of  claim 5 , wherein the selecting of the optimum reference image candidate comprises selecting an input image having a maximum value, from among the standard deviation difference values for the input images, as the optimum reference image candidate. 
     
     
         7 . The method of  claim 5 , wherein the ranking of the suitability of the input images comprises determining order of the suitability of the input images in descending powers of the standard deviation difference values. 
     
     
         8 . The method of  claim 1 , wherein the input images comprise images having different views obtained by multiple cameras. 
     
     
         9 . A color correction apparatus for performing color correction when stitching panorama video based on input images, the apparatus comprising:
 a reference image candidate selection module for selecting an optimum reference image candidate from the input images based on standard deviations for overlapping regions between the input images;   a color correction module for performing color correction on the input images based on the optimum reference image candidate; and   a reference image candidate validation module for validating the optimum reference image candidate based on the color-corrected input images.   
     
     
         10 . The color correction apparatus of  claim 9 , wherein the reference image candidate validation module derives a comparison value between the color-corrected input images and the input images prior to the color correction and determines the optimum reference image candidate to be a final reference image depending on whether or not the comparison value satisfies a predetermined threshold,
 wherein the comparison value comprises at least one of a contrast value, an edge preservation value, and a value indicative of a percentage change in a saturation of color between the color-corrected input images and the input images prior to the color correction.   
     
     
         11 . The color correction apparatus of  claim 10 , wherein the reference image candidate validation module selects a next optimum reference image candidate from the input images based on the standard deviation if, as a result of the determination, it is determined that the comparison value does not satisfy the predetermined threshold. 
     
     
         12 . The color correction apparatus of  claim 10 , wherein the reference image candidate validation module changes the predetermined threshold if the final reference image is not present in the input images and derives the final reference image based on the changed threshold. 
     
     
         13 . The color correction apparatus of  claim 9 , wherein the reference image candidate selection module calculates a standard deviation for an overlapping region between two neighboring input images after geometric correction is performed on the input images, calculates a standard deviation difference value for each of the input images based on the standard deviation, and ranks a suitability of the input images for selecting the optimum reference image candidate based on the standard deviation difference value. 
     
     
         14 . The color correction apparatus of  claim 13 , wherein the reference image candidate selection module selects an input image having a maximum value, from among the standard deviation difference values for the input images, as the optimum reference image candidate. 
     
     
         15 . The color correction apparatus of  claim 13 , wherein the reference image candidate selection module determines order of the suitability of the input images in descending powers of the standard deviation difference values. 
     
     
         16 . The color correction apparatus of  claim 9 , wherein the input images comprise images having different views obtained by multiple cameras.